1. Field of the Invention
The present invention relates to a combustor, particularly to a combustor applied in thermophotovoltaic system.
2. Description of the Related Art
Various electronic products are vigorously developed today, and so are the correlated markets, such as the related power system (battery). Herein, in order to conquer problems that the traditional batteries merely provide limited ability of storing energy, various studies of enhancing energy in a micro device are contributed. For example, electronic products or power supply systems that have to be continuously operated or that consume high power could be readily portable and able to persistently work by means of the micro combustors applied in the thermophotovoltaic power system (TPV).
Generally, the thermophotovoltaic system mainly comprises three elements: the heat source, the emitter, and the PV cell array. The heat source is provided for heating the emitter, thereby allowing radiation energy generated in time of heating to be converted into electricity. Accordingly, a hot subject that discusses how to utilize the emitter and the photovoltaic cell plate to cooperatively result in great efficiency for driving the thermophotovoltaic system is raised. Moreover, in the micro combustor, a swirling system is commonly applied for increasing residence time of flow, so that the fuel/air mixture is enhanced and concurrently results in a flame stabilization mechanism via generation of a flow recirculation zone in the combustor.
However, when the combustor is physically shrunk to a critical size (less than 1 cm), the structure thereof provides little room for the fuel and the air to be mixed. As a result, the fuel and the air are mixed imperfectly, and the correlated heat recirculation is insufficient for the flame stabilization. Hence, thermal dispersion augments and the emitter adversely offers inadequate light energy for the conversion into electricity through the photovoltaic cell plate. Herein, in the conventional thermophotovoltaic system, the emitter is mostly made of silicon carbide (Sic). The advantage of the silicon carbide is that it is able to resist high temperature and it is a near-blackbody, whose radiant intensity reaches 0.9. Nonetheless, the radiant spectrum of the silicon carbide is directed to a broad spectrum, meaning that when the surface temperature of the silicon carbide reaches about 1000 K, most energy is distributed out of the spectrum scope that the photovoltaic cell plate is capable of converting, which is thus wasteful. Further, photons that are not absorbed unfavorably fall on the ultrared section, so the photovoltaic cell plate is accordingly heated up since more thermal radiation is absorbed, which readily results in failure of the photovoltaic cell plate due to the overheating temperature. Obviously, which material is adopted for making the emitter is one of the most important factors that influence the performance of the existing combustor.